Ore concentration



Patented Sept. 26, 1933 UNITED STATES I I 1,927,939 PATENT OFFICE to Phosphate Recovery .Corporation,

New

York, N. Y., a corporation of Delaware No Drawing. Application June 2, 1932 Serial No. 615,031

1'0 Claims. (01. 209-166) This invention relates to ore concentration and is herein illustrated as applied to so-called Florida,

pebble phosphate rock, yielding a concentrate rich in so-called bone phosphate of lime.

According to the present invention, the concentration may be effected by procedures carried out with the aid of novel agents which include the organic materials known as naphthenic acids, usually in the form of sodium salts of those acids.

The most useful of the naphthenic acid materials so far used have been those obtained in the refining of petroleum, and associated with more or less unsaponifiable oil. These, and most commercially available naphthenic acid materials are found to be extremely effective, although under parallel conditions/fiphthoic acids proved comparatively useless. Such derivatives as orthotoluic acid, tetra-hydronaphthoic acid, and hexahydro-ortho-toluic acid, all proved comparatively useless, while the so-called naphthenic acids derived from petroleum compared favorably with the agents hitherto used in concentration of similar phosphate rock.

It will be noted that no mineral-frothing agent, such as pine oil, is used in the examples set forth below. It is found that naphthenic acids in the proportions described, act as frothing agents to some extent, causing the formation of sufllcient and suitable air bubbles in the pulp to effect the floating of a concentrate economically and. effectively. Thus the need for the pine oil, usually employed, is avoided.

The following examples are taken from laboratory tests carried out in accordance with standardized procedure so as to be comparable with each other and comparable with tests on other agents. It will be noted that in every case a concentrate was obtained of high commercial grade, some of the concentrates being of extraordinary richness. Moreover, very little phosphate was lost in the tailings.

One test was carried out with the refined naphthenic acids of Eastman Kodak Company. These acids were made from the crude naphthenic acid of the Standard Oil Company by distilling at a pressure of 20 mm. in a straight vacuu distilling flask with an air cooled side-arm rec iver. The fraction distilling between 230 C. and 285 C. at that pressure was accepted as refined naphthenic acids.

For the purposes of testing the acids as concentration agents the Eastman naphthenic acid was converted to the sodium salt by treating with an excess of caustic soda solution over that theoretically needed to saponify the acid. The resulting solution was added to)an aqueous pulp containing to 70% (dry weight) of feed from a plant of the Phosphate Recovery Corporation near Mulberry, Florida. The feedhad been washed, ground, classified and deslimed until it was mostly from -20 to +200 mesh of phosphate grains and quartz and gangue grains.

The thick pulp was stirred in a glass jar both with the sodium naphthenate and also with added insoluble and unsaponifiable oil, such as fuel oil, and the alkali, caustic soda, so that there was present altogether caustic soda 0.5 pounds, fuel oil 2 pounds, and Eastman Kodak Co. naphthenic acid 3 pounds, all per ton of solids in the pulp. The thoroughly mixed pulp, containing the fractions of a percent of these agents, measured on the dry weight of the pulp, was transferred to a minerals separation subaeration testing machine, diluted with water, agitated, and a float rapidly separated. This float was then'cleaned by reagitation in the same machine with added water to yield a cleaner or final concentrate and a middling. The middling, in commercial operations would be separated into a useful concentrate and a tailing or waste. The results are shown in the following table:

% wr. B. P. L. Ins. g- Ratio A naphthenic acid from the Port Arthur Refinery of the Texas Company was used in another test. The naphthenic acid materials had:

Saponifiable content 69% Saponification value 129 Neutralization-number 122 -The purified naphthenic acids tested as follows:

Saponification number 176.3 Neutralization number 172.8 Specific gravity 0.9845 Flash Cleve. open 355 F. Fire Cleve. open 425 F.

Viscosity, Saybolt, Universal at- 210 F. 96 sec. Color, according to the Lovi- These crude naphthenic acid materials were found to serve satisfactorily in flotation concentration when added to the pulp without previous Saponification. They may become saponified in the alkaline pulp.

To another lot of the same kind of pulp were aqueous solution, 2.5 pounds fuel oil, and 2.5 pounds-of the above-described crude naphthenic acid materials, all per ton of dry material. The same procedure was followed to concentrate the phosphates in the pulp with the results shown in the following table:

%Wt. B. Pl L. Ins. Q P- Ratio 32. o 74. 15 1. s1 93. 5 a. 03 5. 10.52 -2. 62.1 1.91 4.5

Naphthenic acid'made for Shell Eastern Petroleum Products, Inc., by their west coast associate, a by-product of Edeleanu treated California crude, was used in another test. The naphthenic acid material had:

Specific gravity at 60 F 0. 941 Moisture by weight below 1% Free organic acid, as M. G. of KOH 50 Organic acid equivalent to oleic 25.

Free sulphuric acid and other mineral acids absent.

Neutral fat, calculated as olein 4. 6% Unsaponifiable matter '70. 4% Saponifiable matter 29.6% Sapbniflcation value 59.2 Iodine value- 21.0 Cold tes 0 F. Free sulphur None Combined sulphuric acid (calculated as S03) 1. 54% Ash 0.029% Saybolt viscosity, universal at 100 F 746 These acids were also found to serve satisfactorfly in flotation concentration when added to the pulp without previous saponiflcation.

To another lot of the same kind of pulp were 1 added separately 1.1 pounds caustic soda in 10% solution, 1 pound fuel oil, and pounds of the:

% Wt. B. P. L. Ins. gff Ratio Feed o. 11.

19. a 74. 14 a 81 ea 4 5. 1s Midd 2. 2a a 6 The A-naphthenic acids of the Union Oil Company of California were used in another test. The naphthenic material had:

These crude acids were also found to serve satisfactorily in flotation concentration when added to the pulp without previous saponification.

' pulp with the following results:

B. P. L.

Ins. Rec.

% Wt. B. P. L. Ratio won-- The B-naphthenic acids of the Union Oil Company of California were used in another test.

The naphthenic material had:

Gravity Flash test Fire test Viscosity at 210 F Color, dark brownish red.

Acid number (phenol-phthalein) Approximate content of crude naphthenic acids 40 to 50% Apparent acid number of purified naphthenic acids (phenol-phthalein) 145 to 155 1 These crude acids were also found to serve satisfactorily in froth flotation concentration when added to the pulp without previous saponification.

To another lot of the same kind of pulp were added separately 1 pound of caustic soda in 10% solution, 3 pounds of fuel oil, and 3 pounds of the above-described naphthenic acids. The same procedure was followed to concentrate the phosphates in the pulp with the following results:

13 Baum 380 F. 420 F.

.%wt. B. P. L. 1111. 2 Ratio It is also found that phosphate pulps which have been treated in the manner described, with the naphthenic acid materials and usually with the other-agents named above may be caused to, yield concentrates rich in phosphates by agitation of the flowing pulp upon a vibrating table so that the phosphate concentrate comes off the long side of the table and the silica gangue comes off the end of the table as if it were the heavier ingredient of the pulp.

Having thus described certain embodiments of the invention, what is claimed is:

1. The process of concentrating a phosphatebearing material which consists in agitating a pulp of the phosphate-bearing material in the presence of naphthenic. acid material so that concentratiori is effected and is substantially dependent upon the presence of naphthenic acid material, and separating the concentrate 2. The precess of concentrating a phosphatebearing material which consists in agitating and 145 aerating a pulp of the phosphate-bearing material to form a float in the presence of naphthenic acid material so that phosphate concentration is effected in the float and is substantially dependent upon the presence of naphthenic acid 150 material, and separating the float.

3. The process of concentrating a phosphatebearing material which consists in agitating and aerating an alkaline pulp of the phosphate-bearing material to form a float in the presence of naphthenic acid material so that phosphate conce'ntration is efi'ected in the float and is substantially dependent upon the presence of the naphthenic acid material, and separating the float.

4. The process of concentrating a phosphatebearing material which consists in agitating a thick alkaline pulp of the phosphate-bearing material in the presence of naphthenic acid material, thinning the pulp, further agitating so that concentration is substantially dependent upon the presence of the naphthenic acid material, and separating the concentrate.

5. The process of concentrating a phosphatebearing material which consists in agitating a thick alkaline pulp of the phosphate-bearing material in the presence of naphthenic acid material, thinning the pulp, further agitating and aerating the pulp to form a float in the presence of the naphthenic acid material so that concentration is efiected in the float and is substantially dependent upon the presence of the naphthenic acid material, and separating the float.

6. The process of concentrating a phosphatebearing material which consists in adding caustic alkali and naphthenic acid and unsaponiflable and insoluble' oilto a pulp of the material, and

agitating the pulp so that a concentrate sepa rates.

7. The process of concentrating a phosphatebearing material which consists in adding caustic alkali and naphthenic acid and unsaponifiable and insoluble oil to a thick pulp of the phosphatebearing material, thinning the pulp, and agitating so that a concentrate separates.

8. The process of concentrating a phosphatebearing material which consists in adding caustic soda and naphthenic acid and unsaponiflable and insoluble oil to a thick pulp of the phosphatebearing material, thinning the pulp, agitating and aerating the pulp so that a float concentrate forms, and separating the float.

pulp of the phosphate-bearing material, and

agitating so that a concentrate separates.

FRANCIS F. JOHNSTON.

9. The process of concentrating aphosphate- 

